Elasto-plastomeric prefabricated waterproofing membrane whose compound is composed of distilled bitumen, plastomers, elastomers and polyolefin’s (APAO) obtained from metallocene catalysis polymerization, with molecular weight and selected tacticity. This membrane is reinforced with a woven non woven single strand composite spunbond polyester fabric, offering very high mechanical characteristics and excellent dimensional stability. The waterproofing compound has a special inorganic and non toxic additive which confer to the product a flame retardant action.